1、 Eight numbers are arranged in a row, two adjacent numbers are required to be mutually prime 2、 For an Expo project, Party A and Party B can cooperate for seven months to complete. After five months of cooperation, all members of team a and the number of team B will adjust to do other work, and the rest will finish the project in six months. If the project is completed by Party A and Party B alone, it will take two months for Party A and two months for Party B (the result can be a decimal) 3、 As shown in the figure below on the left, the areas of RABC, refg and quadrilateral ACEG are equal, with AE / / Gd, BC: EC = 3:1

1、 1728
2、 12, 16.8
3、 2:1:4

It is known that a, B, C and D are suitable for a + B = C + D, and a ^ 3 + B ^ 3 = C ^ 3 + D ^ 3. Verify that a ^ 2007 + B ^ 2007 = C ^ 2007 + D ^ 2007

A ^ 3 + B ^ 3 = (a + b) ((a + b) ^ 2-3ab) = (B + D) ((B + D) ^ 2-3bd), from a + B = B + D, ab = CD. (A-C) (A-D) = a ^ 2-A (B + D) + CD = a ^ 2-A (a + b) + AB = 0. A = C, B = D; or a = D, B = C. so a ^ 2007 = C ^ 2007, B ^ 2007 = D ^ 2007; or a ^ 2007 = D ^ 2007, B ^ 2007 = C ^ 2007

1: The temperature at noon on a certain day is 7 ℃. The temperature at 4 a.m. is 9 ℃ lower than that at noon, and the temperature at dusk is 4 ℃ lower than that at noon,
2: The external standard storage temperature of a certain brand milk bottle is (4 + the lower one - 2) ℃, so we can know what temperature range is suitable for storage?
The altitude of a is 50m, that of B is 30m, and that of C is - 20m?

1: The temperature at noon on a certain day is 7 ℃, the temperature at 4:00 in the morning is 9 ℃ lower than that at noon, and the temperature in the evening is 4 ℃ lower than that at noon

In the experiment of "studying the factors that affect the size of sliding friction", some students put forward that the size of sliding friction is related to the contact area
How do you think the experiment should be designed for this study

1. Find a rectangular box, the roughness of each side should be the same, and it has three different areas
2. Use a spring dynamometer to pull the box to move in a straight line at a constant speed, measure the pulling force, that is, the friction force on the box, and record it
3. Repeat the second step for each surface of different area
4. Finally, compare the three friction forces. If they are the same, it means that the friction force has nothing to do with the contact area. If they are not the same, it means that the friction force has something to do with the contact area

If the equation | X-2 | + a = 0 has no solution, there is only one solution for | 2x-3 | + B = 0, and there are two solutions for | 3x-4 | + C = 0, then the size relation of a, B and C is?

A must be greater than zero, B only one must be less than zero, C has two solutions must be less than or equal to zero

A railway is 699 kilometers long, and a train runs 69 kilometers per hour. One hour after the freight train leaves, the passenger train runs 71 kilometers per hour. In a few hours, the two trains will meet
I'm in a hurry. Come on

4.5 hours
Process: 699-1 * 69 = 630 / (69 + 71) = 4.5

Given the set a = {- 9, - 2, - 1,0,1,2,3}, B = {- 2, - 1, - 2}, then a ∩ B =?

A ∩ B includes both a and B
So a ∩ B = {- 2, - 1,2}

Factorization of a ^ 2-5A + 6?

A ^ 2-5A + 6 = (A-3) (A-2) help each other

The fruit wholesale department shipped 480KG apples, which is 4 / 5 of the weight of oranges. How many kg oranges?

480÷4/5=480*5/4=600
A: 600 kg of oranges

Fill a bottle with water, pour out half of all the water, then pour in the same amount of alcohol, pour out another third of all the solution, and then fill it with alcohol

Let n times of filling, then the remaining alcohol = (1 / 2) ^ n, that is, half of the n power